HD64F3694HV Datasheet, PDF (320/452 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Tiny Series

Section 18 Power-On Reset and Low-Voltage Detection Circuits (Optional)
RES
CRES
Noise canceler
Noise canceler
φ
CK
PSS
R
OVF
R
Q
S
Power-on reset circuit
Internal reset
signal
Vcc
Ladder
resistor
Vreset
+
−
LVDRES
Vint
+
−
LVDINT
Reference
voltage
generator
[Legend]
PSS: Prescaler S
LVDCR: Low-voltage-detection control register
LVDSR: Low-voltage-detection status register
LVDRES: Low-voltage-detection reset signal
LVDINT: Low-voltage-detection interrupt signal
Vreset: Reset detection voltage
Vint:
Power-supply fall/rise detection voltage
LVDCR
Interrupt
control
circuit
LVDSR
Interrupt
request
Low-voltage detection circuit
Figure 18.1 Block Diagram of Power-On Reset Circuit and Low-Voltage Detection Circuit
18.2 Register Descriptions
The low-voltage detection circuit has the following registers.
• Low-voltage-detection control register (LVDCR)
• Low-voltage-detection status register (LVDSR)
18.2.1 Low-Voltage-Detection Control Register (LVDCR)
LVDCR is used to enable or disable the low-voltage detection circuit, set the detection levels for
the LVDR function, enable or disable the LVDR function, and enable or disable generation of an
interrupt when the power-supply voltage rises above or falls below the respective levels.
Rev.5.00 Nov. 02, 2005 Page 290 of 418
REJ09B0028-0500